“When the going gets tough, the tough get going, and nowhere is tougher than the ULTIMATE MONSTER BATTLE ARENA”
The world of Ultimate Monster Battle Arena is ever changing, as are its Trainers and competitors: working to make themselves stronger, better, faster - to push themselves to be better at new things. They need to push themselves, and push themselves they shall.
As such, each turn in Ultimate Monster Battle Arena you may pick a new Skill to learn that your character has all the pre-requisite Skills for and relates to what your character has been doing with their downtime this turn. Your user page will be updated by the GMs to reflect which Skills are available to you across the game. You make this choice as part of your turnsheet, and at the end of the turn the Skill will be available to you automatically - you may choose to explain your improvement however you wish in character (“I was training every night” is as valid as “I became an expert in Archaeotech overnight by reading everything”)
You may not gain extra Quirks and Flaws using Advancement - these are only gained through other means. Similarly you may not improve your Monster in this way.